A key factor in running a smartphone platform is delivering desired services to your users. Whether that means tending to an app store or routing instant messages, this is the kind of stuff that users who have got on-board with your platform look for its creator to provide. That’s a fine way to do business, but if you want to really reach as large an audience as possible, sometimes those services need to spread beyond the platform itself. That may have been what Microsoft was thinking for its latest digital music offering, which will be reaching beyond the Windows 8 and Windows Phone 8 spheres to eventually come to Android and iOS.

Xbox Music will make its debut on Microsoft platforms, but will eventually spread to other smartphones. The service, which consists of both streaming audio and a digital storefront for track sales, will arrive as a free, ad-supported version for Windows 8. Coughing up $10 a month will remove those ads and extend the service to Xbox and Windows Phone 8 devices.

There’s no word on just when the Android and iOS versions of Xbox Music will become available, nor on pricing for them. If there’s no free option for Windows Phone 8, we can’t imagine the situation would be any different on either of them. That could make it a tough sell when there are already free alternatives available, but perhaps bundling-in Xbox access could still make it attractive for gamers who happen to be on iOS or Android.